Bio-Med Roundup

This month in Bio-Med Roundup:
  • Cherezov et al. and Rosenbaum et al. revealed high-resolution structural insights into the human β2-adrenergic receptor.
  • Candille et al. showed that a mutation in a gene encoding an antimicrobial peptide causes black coat color in dogs.
  • Wood et al. described the genomic landscapes of human breast and colorectal cancers.
  • Kumar et al. reported the discovery of a new molecular cue that promotes limb regeneration in newts.
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This month’s Bio-Med Roundup is sponsored by:
Barnes & Noble

Start your holiday shopping right! For a limited time you’ll receive 10% off everything from Barnes & Noble .com. From November 30th through December 17th every time you shop through www.bn.com/aaas you’ll receive 10% off your order. Terms and conditions: Special savings only available through www.bn.com/aaas. This offer cannot be combined with Barnes & Noble Membership. Offer is not available in Barnes & Noble stores.



GENETICS
 
Sex-Linked Genetic Influence on Caste Determination in a Termite (9 November 2007)
Y. Hayashi, N. Lo, H. Miyata, O. Kitade
Assignment of termites to sterile worker or reproductive castes, previously thought to be determined solely by environmental conditions, has a critical genetic component.

Widespread Monoallelic Expression on Human Autosomes (16 November 2007)
A. Gimelbrant, J. N. Hutchinson, B. R. Thompson, A. Chess
Rather than being expressed from both the maternal and paternal alleles, 5% of human genes, a surprisingly large fraction, are expressed from only one allele.
See related Perspective.

A β-Defensin Mutation Causes Black Coat Color in Domestic Dogs (30 November 2007)
S. I. Candille, C. B. Kaelin, B. M. Cattanach, B. Yu, D. A. Thompson, M. A. Nix, J. A. Kerns, S. M. Schmutz, G. L. Millhauser, G. S. Barsh
Identification of a gene causing black coat color in dogs reveals a surprising new role for a protein family previously implicated in the body’s defense against microbes.
See related Perspective.

Genome-Wide Experimental Determination of Barriers to Horizontal Gene Transfer (30 November 2007)
R. Sorek, Y. Zhu, C. J. Creevey, M. P. Francino, P. Bork, E. M. Rubin
Characterization of gene families that cannot be cloned in the common bacteria Escherichia coli suggests that increased dosage and expression of certain genes are toxic to the host. See related Perspective.

A Melanocortin 1 Receptor Allele Suggests Varying Pigmentation Among Neanderthals (30 November 2007)
C. Lalueza-Fox, H. Römpler, D. Caramelli, C. Stäubert, G. Catalano, D. Hughes, N. Rohland, E. Pilli, L. Longo, S. Condemi et al.
Neanderthals carried a variant of a skin cell receptor similar to that in modern Europeans, suggesting that their pigmentation may have been similarly variable.

The Obesity-Associated FTO Gene Encodes a 2-Oxoglutarate-Dependent Nucleic Acid Demethylase (30 November 2007)
T. Gerken, C. A. Girard, Y.-C. L. Tung, C. J. Webby, V. Saudek, K. S. Hewitson, G. S. H. Yeo, M. A. McDonough, S. Cunliffe, L. A. McNeill et al.
A gene that affects an individual’s risk for obesity codes for a protein that removes methyl groups from DNA, although how this function regulates obesity is unclear.


STRUCTURAL BIOLOGY/BIOCHEMISTRY

GNAT-Like Strategy for Polyketide Chain Initiation (9 November 2007)
L. Gu, T. W. Geders, B. Wang, W. H. Gerwick, K. Håkansson, J. L. Smith, D. H. Sherman
An enzyme in cyanobacteria that unexpectedly acts as an S-acetyltransferase and catalyzes decarboxylation can be used for synthesis of an anticancer polyketide.

High-Resolution Crystal Structure of an Engineered Human β2-Adrenergic G Protein–Coupled Receptor (23 November 2007)
V. Cherezov, D. M. Rosenbaum, M. A. Hanson, S. G. F. Rasmussen, F. S. Thian, T. S. Kobilka, H.-J. Choi, P. Kuhn, W. I. Weis, B. K. Kobilka, R. C. Stevens
The 2.4 angstrom structure of the human β2-adrenergic receptor displays an architecture and helical orientation distinct from that of rhodopsin, the prototypical member of this family.
See related Perspective.

GPCR Engineering Yields High-Resolution Structural Insights into β2-Adrenergic Receptor Function (23 November 2007)
D. M. Rosenbaum, V. Cherezov, M. A. Hanson, S. G. F. Rasmussen, F. S. Thian, T. S. Kobilka, H.-J. Choi, X.-J. Yao, W. I. Weis, R. C. Stevens, B. K. Kobilka
Replacing part of the β2-adrenergic receptor allows an accurate determination of the receptor’s structure, showing how ligand binding activates G proteins.
See related Perspective.

Direct Observation of Chaperone-Induced Changes in a Protein Folding Pathway (30 November 2007)
P. Bechtluft, R. G. H. van Leeuwen, M. Tyreman, D. Tomkiewicz, N. Nouwen, H. L. Tepper, A. J. M. Driessen, S. J. Tans
Single-molecule measurements reveal how the chaperone SecB affects the folding pathway of maltose binding protein to assist its translocation across the cytoplasmic membrane in bacteria.

Carbon Dioxide Activation at the Ni,Fe-Cluster of Anaerobic Carbon Monoxide Dehydrogenase (30 November 2007)
J.-H. Jeoung and H. Dobbek
Structures of a carbon monoxide dehydrogenase enzyme in three different oxidation states show how its nickel-iron cluster activates and reduces carbon dioxide.

Solvent Tuning of Electrochemical Potentials in the Active Sites of HiPIP Versus Ferredoxin (30 November 2007)
A. Dey, F. E. Jenney, Jr., M. W. W. Adams, E. Babini, Y. Takahashi, K. Fukuyama, K. O. Hodgson, B. Hedman, and E. I. Solomon
X-ray absorption studies show that hydration of the active site determines whether iron-sulfur clusters in electron transfer proteins react oxidatively or reductively.


NEUROSCIENCE

Molecular Basis for the Nerve Dependence of Limb Regeneration in an Adult Vertebrate (2 November 2007)
A. Kumar, J. W. Godwin, P. B. Gates, A. Acely Garza-Garcia, and Jeremy P. Brockes
Forelimb regeneration in newts requires concomitant regeneration of the nerve, a necessity that can be circumvented by application of a single protein, nAG.
See related Perspective.

Magnetic Resonance Spectroscopy Identifies Neural Progenitor Cells in the Live Human Brain (9 November 2007)
L. N. Manganas, X. Zhang, Yao Li, R. D. Hazel, S. D. Smith, M. E. Wagshul, F. Henn, H. Benveniste, P. M. Djuric, G. Enikolopov, M. Maletic-Savatic
A fatty acid found only in neural progenitor cells can be monitored by NMR spectroscopy in living humans to show that neurogenesis in the hippocampus decreases with age.

Mnemonic Function of the Dorsolateral Prefrontal Cortex in Conflict-Induced Behavioral Adjustment (9 November 2007)
F. A. Mansouri, M. J. Buckley, K. Tanaka
Dorsolateral prefrontal cortex but not anterior cingulate cortex is essential for conflict-induced behavioral adjustment.

Melatonin Suppresses Nighttime Memory Formation in Zebrafish (16 November 2007)
O. Rawashdeh, N. Hernandez de Borsetti, G. Roman, G. M. Cahill
Zebrafish learn poorly at night, an effect of higher melatonin levels secreted from the pineal gland.

Fast-Forward Playback of Recent Memory Sequences in Prefrontal Cortex During Sleep (16 November 2007)
D. R. Euston, M. Tatsuno, B. L. McNaughton
Neural firing patterns that occur in the prefrontal cortex during a complex task are replayed there during subsequent sleep at about seven times the awake rate.

Time-Dependent Central Compensatory Mechanisms of Finger Dexterity After Spinal Cord Injury (16 November 2007)
Y. Nishimura, H. Onoe, Y. Morichika, S. Perfiliev, H. Tsukada, T. Isa
After suffering damage to the spinal cord, monkeys recover finger function by sequential reorganization of distinct regions of the motor and premotor cortices.

Theory of Mind Is Independent of Episodic Memory (23 November 2007)
R. S. Rosenbaum, D. T. Stuss, B. Levine, E. Tulving
Contrary to current theory, two brain-injured patients who cannot remember their own past experiences can nevertheless infer the thoughts and beliefs of others.

Social Comparison Affects Reward-Related Brain Activity in the Human Ventral Striatum (23 November 2007)
K. Fliessbach, B. Weber, P. Trautner, T. Dohmen, U. Sunde, C. E. Elger, A. Falk
When two subjects play a game in which equal performance is rewarded inequitably, the reward center of the brain responds to the relative, not the absolute, payment.

Hold Your Horses: Impulsivity, Deep Brain Stimulation, and Medication in Parkinsonism (23 November 2007)
M. J. Frank, J. Samanta, A. A. Moustafa, S. J. Sherman
L-Dopa, a common treatment for Parkinson’s disease, impairs certain forms of learning, whereas deep brain stimulation inappropriately accelerates decision making.

Expression and Function of Junctional Adhesion Molecule–C in Myelinated Peripheral Nerves (30 November 2007)
C. Scheiermann, P. Meda, M. Aurrand-Lions, R. Madani, Y. Yiangou, P. Coffey, T. E. Salt, D. Ducrest-Gay, D. Caille, O. Howell
A protein that forms particularly tight junctions between intestinal or endothelial cells also seals the ends of the myelin wrapping around nerve axons.

Social Integration of Robots into Groups of Cockroaches to Control Self-Organized Choices (16 November 2007)
J. Halloy, G. Sempo, G. Caprari, C. Rivault, M. Asadpour, F. Tâche, I. Saïd, V. Durier, S. Canonge, J. M. Amé et al.
Small autonomous robots integrated into groups of cockroaches can influence collective decision making and coax the group toward an inappropriate shelter.


CELL/DEVELOPMENTAL BIOLOGY
 
A Gene Regulatory Network Subcircuit Drives a Dynamic Pattern of Gene Expression (2 November 2007)
J. Smith, C. Theodoris, E. H. Davidson
The ring of gene expression that sweeps across sea urchin embryos is controlled by a regulatory circuit that generates a wave of activation, followed by a wave of repression.

TARP Auxiliary Subunits Switch AMPA Receptor Antagonists into Partial Agonists (2 November 2007)
K. Menuz, R. M. Stroud, R. A. Nicoll, F. A. Hays
A quinoxalinedione glutamate receptor antagonist becomes an agonist when the receptor acquires an extra subunit, coupling changes in ligand binding to opening of the channel.

Ordered Phosphorylation Governs Oscillation of a Three-Protein Circadian Clock (2 November 2007)
M. J. Rust, J. S. Markson, W. S. Lane, D. S. Fisher, E. K. O’Shea
The cycling of three protein components comprising the circadian clock in cyanobacteria is driven by a pattern of sequential phosphorylation that can be described mathematically.
See related Perspective.

IRE1 Signaling Affects Cell Fate During the Unfolded Protein Response (9 November 2007)
J. H. Lin, H. Li, D. Yasumura, H. R. Cohen, C. Zhang, B. Panning, K. M. Shokat, M. M. LaVail, P. Walter
When misfolded proteins accumulate within the endoplasmic reticulum, protective responses are initiated but prolonged stress ultimately triggers cell death pathways.

A Bifunctional Bacterial Protein Links GDI Displacement to Rab1 Activation (9 November 2007)
M. P. Machner and R. R. Isberg
The bacterium that causes Legionnaires’ disease recruits a host protein that regulates vesicle trafficking by mimicking host-activating proteins.

Rheb Activates mTOR by Antagonizing Its Endogenous Inhibitor, FKBP38 (9 November 2007)
X. Bai, D. Ma, A. Liu, X. Shen, Q. J. Wang, Y. Liu, Y. Jiang
Nutrients turn on a regulator of cell growth and proliferation by displacing an inhibitor of the regulator’s kinase activity with a small guanosine triphosphatase.
See related Perspective.

Requirement of Inositol Pyrophosphates for Full Exocytotic Capacity in Pancreatic β Cells (23 November 2007)
C. Illies, J. Gromada, R. Fiume, B. Leibiger, J. Yu, K. Juhl, S.-N. Yang, D. K. Barma, J. R. Falck, A. Saiardi, C. J. Barker, P.-O. Berggren
Pancreatic βcells maintain high amounts of the signaling molecule inositol pyrophosphate, assuring a ready release of insulin in response to metabolic demands.
See related Perspective.


IMMUNOLOGY
 
Disentangling Genetic Variation for Resistance and Tolerance to Infectious Diseases in Animals (2 November 2007)
L. Råberg, D. Sim, A. F. Read
In addition to developing resistance to parasite infection, mice can evolve to tolerate malarial parasites by limiting the damage caused by their presence.

Promotion of Tissue Inflammation by the Immune Receptor Tim-3 Expressed on Innate Immune Cells (16 November 2007)
A. C. Anderson, D. E. Anderson, L. Bregoli, W. D. Hastings, N. Kassam, C. Lei, R. Chandwaskar, J. Karman, E. W. Su, M. Hirashima et al.
A cell surface immune receptor, which usually suppresses immune responses, unexpectedly promotes inflammation when activated on immune cells of the brain.

Efficient Transplantation via Antibody-Based Clearance of Hematopoietic Stem Cell Niches (23 November 2007)
A. Czechowicz, D. Kraft, I. L. Weissman, D. Bhattacharya
An antibody-based procedure can deplete the preexisting bone marrow stem cells in mice, allowing easy repopulation by transplanted stem cells.

5’-Triphosphate–Dependent Activation of PKR by RNAs with Short Stem-Loops (30 November 2007)
S. R. Nallagatla, J. Hwang, R. Toroney, X. Zheng, C. E. Cameron, P. C. Bevilacqua
A pathogen-sensing protein of the innate immune system recognizes the 5’-triphosphate structures of single-stranded RNA present in many bacteria and viruses.


MOLECULAR BIOLOGY

Telomeric Repeat–Containing RNA and RNA Surveillance Factors at Mammalian Chromosome Ends (2 November 2007)
C. M. Azzalin, P. Reichenbach, L. Khoriauli, E. Giulotto, J. Lingner
In mammals, RNA is transcribed from repetitive DNA at the ends of chromosomes and, along with other regulatory proteins, is incorporated locally into silenced chromatin.

Bypass of DNA Lesions Generated During Anticancer Treatment with Cisplatin by DNA Polymerase η (9 November 2007)
A. Alt, K. Lammens, C. Chiocchini, A. Lammens, J. C. Pieck, D. Kuch, K.-P. Hopfner, T. Carell
A specialized polymerase successfully replicates damaged DNA by partially compensating for distortion of the helix introduced by the lesion.

Transposase-Derived Transcription Factors Regulate Light Signaling in Arabidopsis (23 November 2007)
R. Lin, L. Ding, C. Casola, D. R. Ripoll, C. Feschotte, H. Wang
Transcription factors that modulate light responses in plants have been co-opted from an ancestral transposon, suggesting that mobile elements are a driving force in evolution.


MEDICINE
 
Menin Controls Growth of Pancreatic β-Cells in Pregnant Mice and Promotes Gestational Diabetes Mellitus (2 November 2007)
S. K. Karnik, H. Chen, G. W. McLean, J. J. Heit, X. Gu, A. Y. Zhang, M. Fontaine, M. H. Yen, S. K. Kim
A study of mice identifies a protein that may malfunction in gestational diabetes, a common complication of pregnancy.

The Genomic Landscapes of Human Breast and Colorectal Cancers (16 November 2007)
L. D. Wood, D. W. Parsons, S. Jones, J. Lin, T. Sjöblom, R. J. Leary, D. Shen, S. M. Boca, T. Barber, J. Ptak et al.
Tumor growth seems to be driven by many genes mutated at low frequencies, most of which act through well-known signaling pathways.
See related Perspective.


PLANT SCIENCE
 
A High-Resolution Root Spatiotemporal Map Reveals Dominant Expression Patterns (2 November 2007)
S. M. Brady, D. A. Orlando, J.-Y. Lee, J. Y. Wang, J. Koch, J. R. Dinneny, D. Mace, U. Ohler, P. N. Benfey
As roots of Arabidopsis develop and grow, genes are expressed in complex patterns that have not been previously apparent.

Plants Tolerant of High Boron Levels (30 November 2007)
K. Miwa, J. Takano, H. Omori, M. Seki, K.Shinozaki, T. Fujiwara
An Arabidopsis protein enhances the borate efflux from roots; incorporating its gene into crops may help improve their growth in arid soils containing excess boron.

Boron-Toxicity Tolerance in Barley Arising from Efflux Transporter Amplification (30 November 2007)
T. Sutton, U. Baumann, J. Hayes, N. C. Collins, B.-J. Shi, T. Schnurbusch, A. Hay, G. Mayo, M. Pallotta, M. Tester, P. Langridge
Wild barley strains that are unusually tolerant of boron have extra copies of a gene that codes for a boron transporter.


This month’s Bio-Med Roundup is sponsored by:
Barnes & Noble

Start your holiday shopping right! For a limited time you’ll receive 10% off everything from Barnes & Noble .com. From November 30th through December 17th every time you shop through www.bn.com/aaas you’ll receive 10% off your order. Terms and conditions: Special savings only available through www.bn.com/aaas. This offer cannot be combined with Barnes & Noble Membership. Offer is not available in Barnes & Noble stores.